The valid value for sIDType is "CUID". You can get the CUID and SI_ID values from the properties of the report in the CMC. if you use the SI_ID value for iDocID, you don't need the sIDType parameter.

NOTE 1: Using sIDType and iDocID tends to be MUCH more stable than using sType and SDocName because you can potentially have multiple reports with the same name.

NOTE 2: If you're passing session information to the URL, you CANNOT use the same session over and over again - at some point it will expire and the link will no longer work.

You can get the OpenDocument Documentation in the Development Information section for your version of BO at http://help.sap.com/bobip.

If you still can't get it to work, please post the full URL of what you're trying to do without "http://" in front of it so that it doesn't get automatically converted to a link. I'll take a look at it to see if I see anything might be wrong with it.